Trigonometric calculator



April 2s, 195o v. A. sci -IQENBERG 4 TRI-GoNoMETRIc CAIIQGULATOR 2 Sheets-Sheet 1 Filed Nov, 121,- 194162 I'NVENTOR V GIL A. SCH ENBERG- n g1 rn ATTORNEYS April 25, 1950 v. A. scHoENBERG uTRIGOIIONIE'IRIC CALCUATQR 2 Sheets-Shes?l 2 Filed NOV. 21, 1946 UNAIIINI INVENTOR BY. VIRGIL A. SCHOENBERG ATTORNEYS Patented Apr. Z5, 1950 UNITED STATES TENT OFFICE TRIGONOMETRIC CALCULATOR Virgil A. Schoenberg, Glen View, Ill.

Application November 21, 1946, Serial No. 711,441

2 Claims. l

This invention relates to trigonometric calculating devices and particularly to such an instrument, embodying pivotally connected graduated protractors and straight-edge measuring arms, arranged to set up the known factors of a given trigonometric problem and, by direct reading from the instrument, evaluate the unknown factors of the problem.

The main objects of this invention are to provide an improved trigonometric calculating device whereby trigonometric problems may be evaluated without the aid of texts, tables or formulae; to provide such a device having interchangeable parts of simplified construction; to provide such a device having two basic elements which may be combined in'multiples fol1 the evaluation of substantially any problem in plane trigonometry; to provide an improved trigonometric calculating instrument that may be more easily read and utilized with maps and charts; and to provide such a device of standardized parts which can be manufactured easily, accurately, and at a low cost. y

A specific embodiment of this invention is shown in the accompanying drawings in which:

Figure 1 is a plan view of a calculating instrument embodying the invention and illustrating a manner in which the elements may be combined to provide an instrument for evaluating trigonometric problems.

Fig. 2 is a sectional View of the improved protractor element, as taken on line 2-2 of Fig. 1.

Fig. 3 is a fragmentary sectional view of the same, as taken `on line 3--3 of Fig. 2.

Fig. 4 is a fragmentary plan view of the same, as taken on line 4--4 of Fig. 2.

Fig. 5 is a perspective View of a Vernier for use with the protractor, partly broken away to show its construction, and

Fig. 6 is a sectional view similar to Fig. 2, showing a modiiication of the protractor construction.

In the form shown in the drawings, particularly in Fig. 1 thereof, the improved calculating device comprises three circular protractors l, 2 and 3, and three arms or straight edge members 4, 5 and 6 which are slidlably and pivotally connected to the protractors at their centers so as to coact with the marginal scale of angular measurement on the protractor.

As indicated in Fig. 1, the measuring arms or straight edges are received in slides mounted centrally on the protractor body and are shiftable longitudinally in the said slides. Also, at least one of the slides is pivoted onthe protractor body so that when the parts are assembled as shown in Fig. 1, they may be shifted relative to each other to vary the length of the arms between the protractors and to vary the angular relationship of the parts.

Thus. the protractor elements I and 2 may be set in any desired position or spacing along the arm 6 and the protractor 3 may be set at any desired position along the arms 4 and 5; and any shape of triangle between the centers of the three protractors may be formed.

In the form shown each protractor is a fiat, circular body having a marginal or circular scale preferably arranged to indicate degrees of angular arc or measurement and each arm or straight edge is a fiat member of any desired length having parallel sides and faces and having a longitudinal hairline which may be divided according to any desired or predetermined scale. Also each l arm is provided with an arcuately shaped transversely positioned Vernier member, slidably mounted on the arm and arranged to coact with the marginal scale of one of the protractors with which the arm is directly associated. The vernier is preferably scaled or calibrated to indicate minutes of arc.

In the form shown in Figs. 2 and 3, wherein protractor element has only one of its slides pivotally mounted, the body of the protractor is in the form of a fiat disc 'l having a central recess or depression 3 in which the pivoted or rotatable slide is disposed. The slide is of the box type, rectangular in form and having open ends through which the shiftable arm is passed. This box slide comprises a bottom member 9 and a top member I0 connected by side members or spacers I l and i2 and held together by means of suitable screws I3.

The rotatable box slide is mounted on the protractor body 'l so as to overlie or include the geometric center of the circular protractor scale formed on the body 1 and is arranged to pivot or turn about an axis through the geometric center of said circular scale.

In the arrangement shawn the rotatable box slide is disposed concentrically on the axis or geometric center 4oi the protractor scale and is pivotally connected tothe body l by means of a fiathead .screw I4 which extends through the body l, at the geometric center of the protractor scale, and through the bottom member 5 of the slide. The slide is secured by means of a fiat nut l5 which is countersunl; into the upper surface of the bottom slide member Q so as to be flush thereg with. Also the athead i5, of the screw or bolt.

I4, is countersunk into the opposite face of the body 'I so as to be ush therewith.

The nut i5 is fixed to the screw I4, after it has been properly set in place, so that the box slide may turn freely relative to the screw and nut and, to facilitate such turning, a washer i1 is disposed between the body 'i and the lower slide member 9. The thickness of the washer I'l is preferably guaged so that the upper surface of the bottom slide member 9 will be ush With the scale carrying face of the body 1.

The fixed or non-rotatable box slide shown in Fig. 2 comprises a pair of parallel side members or spacers I8 and I9, and a cover member .2.9, mounted on the body I by means of suitable screws 2! and disposed over the axis of rotation of the rotatable box slide, preferably concentric therewith.

Also, as shown in Figs. 2 and 3, each box slide provided with a spring friction member 22 mounted on one ofthe sidemembers or spacers and arranged to bearagainst the edge of the arm shiitably positioned in the slide. This spring is a dat, curved member heldin place by laterally projecting lugs, or pintles 23, which extend into suitable openings in the bottom and top members 5 and lo ofr theslide,` as shown in Fig. 3. The springil is resilient and is curved so that its central Yportion will projectv into the path of the arm inserted'into t eslide and be frictionally engaged .y

by the side edge of thearm.

'In .the form .of protractor shown in Fig. 2, the lowermost or fixed slide will preferably be positioned on theibcdy .so that the open ends of the slide will be aligned with the 04.80 line of the protractor scale.l Also the cover members and 2!) of thefrotatable and iixed slides respectively, are each provided with a transverse index line which intersects the axis or" rotation, or the geometric center of the protractor scale.

lThesliding Vernier, which is mounted on each arm or straight edge for -coaction with a respective prct-ractor scale, is shown in Fig. 5 and as shown comprises abody 2li having a circularly curved-forward .portion `adapted to t against the edge of the circular protractor body 1. AS shown, the forwardfportion 25 extends laterally on each side of the body 24 and carries, on its upper suriacega scaleg of YVernier measurement proportioned to the `measurements of the pro tractor scale. The zero line of `'thisvernier scale isprci ably kcentered relative to the body 2e and @e ner scale progresses on each side of the zero line in increments representing minutes of arc.

Albox slide comprising side members 2l and 28 anda top or cover member 29 is built onto the upper surface of the body 243 and the ends of this slide are left open to receive the arm or straight edge lio in sliding engagement, lwhich arm has a central hairline 3i positioned to 'be aligned with the cero line of the Vernier scale when the Vernier is mounted on the arm. A spring `32 is provided in one of the side members or" this box slide for frictional engagement with the vedge of the arm when the Vernier is mounted on the arm.

All of the elements of the herein-described calculating-device, except those which of necessity must "ne made of metal, are to Abe constructed of a suitable transparent material such as a clear, colorless plastic, in order that scale markings, etched or cut into the working surface of each element, will be visible through the material.

Thus it will be seen that when the several elements are assembled in the desired arrangement,

for example, the arrangement shown in Fig. 1, the several scale markings are readily visible through the elements though several of the elements are superposed at the point where the reading is to be made.

In the arrangement shown in Fig. l, the arm 6 is considered the base line and is inserted through the xed slides on the underside of the protractors l and 2. The arms E- and 5 are then inserted through the xed and rotatable box slides respectively, of the protractor 3 and then a free end of Aeach of the arms l and 5 are inserted through the upper rotatable box slides of the protractors l `and '2. `When in such arrangement, the elements can bereadily adjusted to form any shape of triangle and when so adjusted, the angular relationship of the arms can be readily read, through the clear transparent material of the elements, from the protractor scale. Also the proportionate length of the arms between the protractor `centers can be readily .determined from suitable scales formed on the arms along lthe longitudinal hairline 3E.

`,As before mentionedthe cover vmembers lll in the uppermost or rotatable box slides are each provided `with a transverse hairline, indicated at to in lLyvhich hairline intersects the center of rotation of the respective box slide. Also a vernici' scale 3d -may-,be provided on the cover members lb for fractional readings or the scale provided on the arms.

As shown in Fig. 1, the AVernier slides are mountedion the respective arms before the armsv are inserted .in the 'box slides of the respective Drotractors and each of the verniers is faced to coact with the edge oi a respective one of the protractor bodies. yFor example, the verniers on the arms 13 and dwill be positioned to coact with the protractors 2 and respectively. The third Vernier will of necessity be mounted on the arm 5 so that the transverse scale carrying portion will eng-age the edge of the protractor l, since the arm 6 is held in the lower fixed slide and only the arm 5 will swing relative to the protractor l.

A modified construction of the improved protractor, wherein both the upper vand lower box slides are rotatable vrelative -to the protractor body, is shown'in Fig. 6. In'this form, the protractorbody 35 is provided with a central recess 3o and 3l' in each face, respectively, and a rotatable box slide is disposed in each recess and mounted so as to turn on an'axis through the geometric conter of the circular protractor scale formed on the body 35. As shown in Fig. 6, the pivot for the boxslides 38 is centered in the protractor body 35 and comprises a bolt 39 which extends through the inner or vbottom members of the box slides '38. The head 4l) of the bolt 3-9 and the nut 4i are each countensunl: in the respective bottom `members ofthe slides so as to be iiush with theioutersurface of `said bottom members, and suitable washers 42 are disposed between the slides andthe body 35 .to permit easy rotation of the slides, the spacers 2 in each case being :of la gauge or thickness such thatthe surface'of the bottom members oi :the Vslide which engages the shiltable .arm will be flush with the respective iace surfaces of the protractor 'body 35.

When this modified form of protractor is used in a vconstruction such as that `shown in Fig. 1, the -protractor body `will be rotatable relative to all of the arms and the fi-'180 line of the protractor scale and may be shifted to any desired position. This 'form of protractor may :be partic-- ularly desirable in those cases where more than 3 protractors and 3 arms are combined to construct the calculating device and, in this respect, it is to be understood that more than 2 protractors may be utilized with any one arm as may be necessary to solve some trigonometrical problems.

The main advantages of this invention reside in the interchangeability of the several elements comprising the calculator construction whereby the elements may be combined in substantially7 any number and arrangement to adapt the calculator to practically every type of problem involving plane trigonometry.

Other advantages reside in the improved protractor construction whereby the form is simplified and whereby scale readings from either the protractor or the arms is more easily and accurately obtained. Still further advantages are to be found in the construction of the calculating device from clear transparent material which permits overlapping relationship of the elements of the device without detracting from the readability of the several scales at a point aligned with the axial center of the protractor.

Although but one specic embodiment of this invention and but two forms of the protractor element thereof are herein shown and described, it will be understood that details of the construction shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

I claim:

1. A calculating device comprising a protractor having a circular scale, and a slide on each side of the protractor with its slide opening flush with the respective face thereof and positioned to include the geometric center of said scale, one of said slides being pivotally mounted on said protractor to turn on an axis through said geometric center, a pair of arms disposed one in each of said slides and shiftable longitudinally therein on the plane of the respective face of said protractor, each of said arms having a longitudinal line intersecting the geometric center of the protractor scale, and an arcuate Vernier disposed transversely on one of said arms and arranged to be independently slidable therealong, said Vernier being disposed in the plane of said scale arranged to coact therewith.

2. A calculating device comprising a plurality of annular disc-like protractors each having a marginal scale and a slide on each of the protractor faces disposed with its slide passage flush therewith and positioned to include the geometric center of the scale, at least one slide on each protractor being pivotally mounted to turn on an axis through the geometric center of the protractor scale, a plurality of arms connecting said protractors, each arm connecting a pair of protractors and being shiftably disposed in re spective slides thereof and on the plane of the respective protractor face, and each arm having a graduated longitudinal line intersecting the geometric centers of the respective protractor scales, and a Vernier disposed transversely on each of said arms and independently slidable therealong to coact with the scale of one of the protractors with which the respective arin connects, each of said Verniers being mounted on its respective arm so as to lie in the plane of the enacting protractor.

VIRGIL A. SCHOENBERG.

REFERENCES CITED The following references are of record in the le of this pa/tent:

UNITED STATES PATENTS Number Name Date 474,846 Miller et al. May 17, 1892 479,198 Watson July 19, 1892 506,416 Colley Oct. 10, 1893 1,661,096 Rowe Feb. 28, 1928 1,880,683 Berman Oct. 4, 1932 2,093,048 Ike Sept. 14, 1937 2,123,674 Gottlieb July 12, 1938 2,239,229 Harris Apr. 22, 1941 2,244,125 Siefker June 3, 1941 

